Field of Endeavor
The present invention relates to filters, equipment, or systems and more particularly to emergency sacrificial sealing method in filters, equipment, or systems.
State of Technology
European Patent Application No. EP 2 412 409 A1 for single-body intumescent gaskets for cold and hot smoke sealing, in particular for fire dampers published Jan. 2, 2010 provides the state of technology information reproduce below.
The present invention relates to intumescent gaskets for hot smoke and also cold smoke sealing, particularly suitable for fire dampers.
Fire dampers are used in the compartmentalisation of fire-fighting zones in ventilation and for air-conditioning systems and their purpose is to avoid the propagation of smoke in the air distribution channels during a fire by means of the closure of the respective blade mounted on said damper.
The closure of the blades generally takes place when a sensing member present thereon reaches the temperature of 72° C.: however the intumescent gaskets mounted on the blade or in the immediate vicinity thereof generally ensure good hot smoke sealing, generally at temperatures higher than 110° C., thanks to the expansion of the intumescent material, but are not suitable for lower temperature smoke sealing.
This is due to the fact that gaskets for fire dampers available to date on the market are formed in actual fact by two different gaskets adjacent one to the other and not integral, each one suitable for performing a different task: the first gasket is suitable for fire damping and hot smoke sealing which is made up of a band (A) in intumescent material having a minimum expansion temperature of 120-200° C., which can also be covered by a profile (B) in plastic, rigid or semi-rigid; the second gasket is suitable for cold smoke sealing which is made up, for example, of expanded polyurethane foam (C), The limits of this technical solution lie in having to use two different gaskets with different function to ensure the functioning of the entire system, and in having to attach the gasket (C), for example in polyurethane foam, close to the other gasket and to the blade by means of appropriate adhesives. Moreover, in the specific case of profiles for intumescents in rigid plastic, for example those for containing intumescent calcium silicates, their elastic and sealing performances are limited due to the reduced adaptability to curvilinear shapes.
To overcome this problem of elasticity and of sealing attempts were made to incorporate the intumescent material, in general intumescent graphite, in a PVC matrix so as to generate a composite suitable for being extruded in flexible tubular form: however the incorporation of intumescent material in a polymeric matrix such as PVC results in a smaller expansion of the intumescent material at the time of use since it expands partially already during the incorporation and/or crosslinking of the tubular article, and therefore with lower the damping performances. Moreover the obtaining of flexible gaskets with smooth surface from said extrudable matrices is difficult and their combustion generates toxic fumes such as hydrochloric acid.
Profiles in plastic are not known to date which are flexible and which contain intumescent material able both to seal against cold smoke and to expand completely during the fire.